Sunday, 21 December 2008

Texture in oil with painting knives

When painting the oil on canvas Chrysanthemums and apples, I used painting knives for both the background and the flower petals. In this post, I will give you more details on the techniques and material used.

Painting the background

I changed the colour and aspect of the background many times for this painting, finally choosing a cool neutral background to make the warm colours of the composition resonate.

To build the foundation, I used a square shaped painting knife. Both the end and the side of the knife create interesting effects. By varying the pressure and the angle the edge of the knife makes with the canvas, you leave more of less paint on the canvas. I also scraped some painting to reveal the original background. I like the contrast you get between heavy sleek applications and the rough texture of the canvas.

If overused, painting knives can give your painting a cheap look. I think this is because you may end end-up with a mosaic of bright pure colours. On the other hand, there is nothing like a painting knife to build texture and give your painting a sculptural feel.

One way to get both texture and subtle colour variation is to glaze over the texture created with painting knives. This way, you re-introduce nuances in tones and colours while keeping the benefit of a strong texture.

Glazing over pure colours also achieves another goal: beautiful transparent and luminous colours.

The process takes time because you need to let your work with the painting knife dry before you can glaze over it. You can speed-up drying time if you mix your paint with Alkyd impasto medium or gel.

I used a technique that decorators are familiar with: On a light textured background, I laid some dark transparent colours mixed with painting medium. Then, I rubbed off the paint with a rag, leaving the glaze in the pits of the textured under painting. By doing this repeatedly with different shades of dark colours, I obtain an interesting background. If you leave the glaze to dry a little bit, then more of the colour stays on the background. The same technique can be employed to weather old wood of building walls in landscape paintings.

Painting the flower petals

For the impasto on the flowers, I mixed the paint with Lefranc & Bourgeois Flemish Medium paste (clear) in tube. It is composed of mastic resin, linseed oil, Aspic spirit and cobalt-zirconium siccative. It takes quickly (2 hours) and becomes hard when dry. It is glossy and transparent and allows precise and profound brush strokes.

A thin rounded knife is ideal to paint flower petals. Note how the shape of the knife blade actually mimics the shape of the petals.

For maximum effect, the thick application of pure light colour is laid on top of the thin darker under painting (see Thick lights over thin darks ). The contrast is also increased by opposing the cool shade of the further petals with the hot colour of the thick petals in the foreground.

I have reposted the photograph of the
Chrysanthemums and apples painting in a larger format, so you can see the details of the brushwork and texture created with the painting knives. To see the larger photograph, just click on the photograph in the post and the larger version will open in a new window.

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